well in arma you already have M4 + ACOG... or AK with scopes. why not just use the same models for example you got an AK. you found a x8 scope ( it would look like a large painkillers box (keep it generic) you right click and install...and your weapon gets removed from inventory and a new one appears on the floor with x8 scope on your rifle (be that PSOP for AK or ACOG for M4... etc)